A tissue paper relates to an absorbent paper based on cellulose fibers which is also called tissue paper base sheet in this field of technology. A typical absorbent paper has a low basis weight, in the range from 10 to 60 g/m2, or 30 to 50 g/m2.
A nonwoven fabric including cellulosic fibers relates to an absorbent paper which is also called nonwoven or web made of fibers like air-laid web in this field of technology. A typical absorbent paper has a basis weight, in the range from 20 to 300 g/m2, or 40 to 60 g/m2.
The document WO 2010/42472 describes fibrous web substrates and a process for printing a series of different graphics in the manufacture of fibrous web substrates, such as tissue and towel products, utilizing flexographic printing with endless belts and having graphic repeats of at least about 58 inches. In addition, these substrates have color to color MD registration of less than about 1.5 mm.
However, this printing apparatus is not adapted to custom print on absorbent sheet products because of the limitation to one pattern/cliché per impression cylinder and also the complexity/time required for changing an impression cylinder in an industrial flexographic printing line. Flexographic printing is well adapted for printing identical pattern at an industrial manufacturing speed (up to 1,000 m/min) for high volume of products (e.g. a thousand absorbent sheet products) and at a low cost.
The document EP 1575778 describes a method of creating high-speed multi-color process images. The method includes providing at least two high operating frequency printheads which are capable of processing phase-change inks, providing at least two phase-change inks, providing a substrate, activating the printheads such that at least two inks pass therethrough, and passing the substrate under the printheads at a rate of at least about 1000 ft/min (i.e. around 305 m/min) so as at least one process image is formed on the substrate. This document also describes a process for achieving high-speed crockfast process printing on a material with phase-change ink. The process includes providing at least an array of printheads capable of processing phase-change inks at frequencies of at least about 20 kHz, providing a material, providing a material transport system capable of transporting the material under the printheads, providing a plurality of phase-change inks, transporting material under the array printheads at a speed of at least 1.000 ft/min, and ejecting ink from at least two of the printheads onto the material so as to form an image.
This document is concerned with the “personal care articles/products” or “personal care absorbent product” such as feminine hygiene articles, diapers, baby pull-on articles, baby wipes, sanitary wipes, wet wipes, baby swim articles, adult incontinence articles, training pants, swim wear, absorbent underpants, wound dressings, nursing pads, time release patches, bandages, mortuary products, veterinary products and the like. However, this printing apparatus is not adapted to print on absorbent substrates that generate fiber dust due to the nature of the product that is running in a converting machine, operating at an industrial speed.
Thus, there is a need to improve quality of printing, uniformity of printing, runnability in a converting machine that may be used to custom print absorbent substrates (tissue papers and/or nonwovens), and also to avoid wasting time on the maintenance of the print heads. Further, this should be obtained in an economical or a cost-effective manner.